Synthesis And Biological Application Of Semiconductor And DNA-Based Composites

Cancer,environmental pollution,aging population and food safety seriously threaten human health,among which cancer is a difficult problem that has not yet been solved in the field of medicine.So far,many methods,including surgery,chemotherapy,radiotherapy,phototherapy,gene therapy,immunotherapy,targeted therapy,and minimally invasive therapy,have been widely used in the treatment of cancer.In order to reduce the side effects of treatment and improve the therapeutic effect,a large number of multifunctional nanocomposite platforms have been developed for early diagnosis and accurate treatment of cancer cells.However,the above functional nanomaterials still have great limitations,such as unclear safety mechanism,unclear pharmacokinetics,the possibility of immunogenicity,inflammatory response and tissue damage.Therefore,researchers expect to develop more simple and flexible design methods to realize the controllable preparation of nanocomposites,and to obtain better performance in precision medic al treatment,such as high sensitivity detection,near infrared imaging,combined treatment and so on.In this study,high biocompatibility materials were selected to construct a new multifunctional nanocomposite platform.Based on the goal of tumor specif ic rapid imaging and accurate treatment,several controllable nanocomposites were designed.This research paper selects high biocompatibility materials to construct a new multifunctional nanocomposite platform.With the goal of tumor-specific rapid imaging and precision treatment as the main point,several simple and controllable nanocomposites are designed for SERS detection of reporting molecular,and then studied its detection mechanism.At the same time,the application of composited materials in enhanced photodynamic therapy and photodynamic and photothermal therapy was explored.The details are as follows:?1?DNA origami composited alloy dimer material was synthesized.Two gold nanoparticles with a diameter of 15 nm,40 nm were assembled on the DNA origam i structure by complementary pairing of the capture chain on the DNA origami and the complementary chain based on modified on the gold particles.DNA origami composited 15 nm gold dimer and DNA origami composited 40 nm gold dimer were formed by that method so that the gap between the two composites is about several nanometers.The results of electron microscope and atomic force characterization show that the of the synthesis method is armed with high yield and high stable for the assembly structure of the composites.The main factor of the electromagnetic strengthening mechanism is calculated,and the strong coupling optical properties of the plasma exciton on the surface of the composite are obtained by a model.Then Rhodamine 6G Raman labeled molecules were uniformly mixed with the two kinds of composites,and the Raman signals of the two composites were measured by confocal Raman spectroscopy,which showed that DNA origami composited 40 nm gold dimer can effectively improve Raman signal and can enhance greatly of the surface enhanced Raman scattering effect.?2?The g-C₃N₄ composite MnO₂ nanomaterials were prepared by one-step redox method.It has the advantages of convenient preparation,high stability and open-type fluorescence response.It is a new and promising bioimaging and therapeutic application material.The g-C₃N₄ nanosheets not only have a high specific surface area and ideal fluorescence characteristics,but also can generate a large amount of singlet oxygen under laser irradiation.The MnO₂ in the composite can consume glutathione?GSH?,thereby reducing the consumption of singlet oxygen by GSH,so the composite can be effectively enhanced photodynamic therapy.?3?Semiconductor quantum dots emitted by near-infrared have the advantages of reducing auto-fluorescence of biological tissues and increasing depth of tissue penetration.In this paper,a one-pot synthesis of near-infrared AgInS₂/ZnS composites was achieved by strictly controlling the acid-base conditions of the reaction.The composite has near-infrared emission and excellent fluorescence imaging capabilities.Under 660 nm laser irradiation,the composite has good photothermal properties,and the composite can effectively produce singlet oxygen.Therefore,the composite has potential applications in photodynamic therapy.